1. Field of the Invention
The present invention relates to a failure diagnostic system of a vehicle, and more particularly to a technique for storing vehicle operation information.
2. Description of Related Art
Recently, the mechatronics technology, which combines the mechanics technology with the electronics technology, has shown the notable progress as a result of the substantial progress in the electronics technology, such as the advent of high performance microprocessors. As part of the progress in the mechatronics technology, various computer systems have been developed for use in vehicles, such as automobiles. These computer systems are used to achieve an improvement in resource consumption, energy consumption, running performance, safety, comfort or the like and are provided in various systems, such as an engine system, a drive system, a running safety system (e.g., a vehicle stability control system, an anti-lock brake system, etc.), an entertainment system and the like of the vehicle.
Among the various computer systems, a demand for achieving a particularly high reliability has been placed on an electronic control unit for controlling a vehicle. For example, if the electronic control unit fails to detect a failure of one particular part of the vehicle, the vehicle may experience a driving trouble or may not be able to continue its driving. To avoid this, one previously proposed electronic control unit is provided with a diagnostic program for diagnosing each corresponding part of the vehicle to improve reliability. That is, operation of each computer and of each sensor is periodically and automatically checked. When a failure of the vehicle occurs, a diagnostic fault code (SAE code) and vehicle operation information are stored in a memory of the electronic control unit. The vehicle operation information shows a state of operation of the vehicle at the time of occurrence of the failure. The vehicle operation information is generally referred to as freeze frame data (FDD), which is vehicle data corresponding to a parameter identification (PID) specified by the regulation.
A service personnel retrieves the diagnostic fault code and the vehicle operation information stored in the electronic control unit by connecting a terminal device to the electronic control unit and identifies a failed part of the vehicle based on the diagnostic fault code and the vehicle operation information.
However, it is sometimes difficult to identify the failed part of the vehicle based on the limited vehicle operation information, to which the corresponding PID is assigned. For example, depending on a type of encountered trouble of the vehicle, a value of an internal parameter used in a particular control operation may be required to identify the corresponding failed part of the vehicle, which causes the trouble of the vehicle.
Furthermore, the vehicle operation information is stored in the electronic control unit only when the corresponding diagnostic fault code is stored in the electronic control unit. Since the vehicle operation information is stored only at the limited times, it is sometimes difficult to identify the failed part of the vehicle based on the vehicle operation information. For example, depending on a type of encountered trouble of the vehicle, change in the vehicle operation information within a limited time period may be required.
That is, because of the variations in the occurrence of the trouble of the vehicle, the failed part of the vehicle sometimes cannot be identified based only on the vehicle operation information, to which the corresponding PID is assigned. Thus, the vehicle operation information needs to be stored depending on the circumstances. Furthermore, besides the time of storing the diagnostic fault code, the vehicle operation information is preferably stored at other times as well.
To address the above disadvantage, in one previous proposal, the diagnostic program implemented in the electronic control unit is rewritten individually depending on each encountered trouble of the vehicle. That is, by the modification of the diagnostic program or addition of an analytic program to the diagnostic program, the vehicle operation information, which is required to identify the failed part of the vehicle, can be stored in the electronic control unit at any required time. Then, a reproduction test for reproducing the occurrence of the failure is performed. The service personnel identifies the failed part of the vehicle based on the vehicle operation information stored in the electronic control unit during the reproduction test.
However, the modification or addition of the diagnostic program requires knowledge of the entire diagnostic program, so that the modification or addition of the diagnostic program needs to be performed by an expert. Furthermore, even when the expert modifies or adds the diagnostic program, a debug operation is required in response to the modification or addition of the diagnostic program, so that time required to modify or add the diagnostic program becomes relatively long, causing inconvenience to a user.
The present invention addresses the above disadvantages. Thus, it is an objective of the present invention to make it easier to collect vehicle operation information for identifying a failed part of a vehicle without requiring expert knowledge of a diagnostic program to allow easy identification of the failed part of the vehicle.
To achieve the objective of the present invention, there is provided a failure diagnostic system including an electronic control unit, which is installed in a vehicle, and a terminal device, which is communicatable with the electronic control unit. The electronic control unit includes a control program for controlling the vehicle and a diagnostic program for diagnosing each predetermined part of the vehicle and for storing vehicle operation information of the vehicle in the electronic control unit. The terminal device is capable of obtaining the vehicle operation information from the electronic control unit. Furthermore, the terminal device is capable of transmitting functional modification information to the electronic control unit. The functional modification information is usable to achieve functional modification of the diagnostic program and is prepared in association with failure information of the vehicle. The electronic control unit is capable of changing at least one of the vehicle operation information to be stored in the electronic control unit and a condition for storing the vehicle operation information in the electronic control unit by executing the diagnostic program to store the vehicle operation information in the electronic control unit based on the functional modification information transmitted from the terminal device.
To achieve the objective of the present invention, there is also provided an electronic control unit for use in a vehicle. The electronic control unit includes a control program for controlling the vehicle and a diagnostic program for diagnosing each predetermined part of the vehicle and for storing vehicle operation information of the vehicle in the electronic control unit. When the electronic control unit externally receives functional modification information that includes at least one of subject information, which specifies the vehicle operation information to be stored in the electronic control unit, and condition information, which specifies a condition for storing the vehicle operation information in the electronic control unit, the electronic control unit creates at least one of a subject table, which corresponds to the subject information, and a condition table, which corresponds to the condition information. The electronic control unit is capable of changing at least one of the vehicle operation information to be stored in the electronic control unit and the condition for storing the vehicle operation information in the electronic control unit by executing the diagnostic program to store the vehicle operation information in the electronic control unit based on the at least one of the subject table and the condition table.